Summary of Impaired Loans (Detail) - Financial Services - USD ($) $ in Millions	12 Months Ended
	Jun. 30, 2016		Dec. 31, 2015
Financing Receivable, Impaired [Line Items]
Impaired loans with a specific reserve	$ 27.9		$ 29.1
Associated allowance	(3.7)		(4.3)
Net carrying amount of impaired loans with specific reserve	24.2		24.8
Impaired loans with no specific reserve	5.9		6.8
Net carrying amount of impaired loans	30.1		31.6
Average recorded investment	34.7	[1]	34.1	[2]
Dealer | Wholesale
Financing Receivable, Impaired [Line Items]
Impaired loans with a specific reserve	2.6		5.0
Associated allowance	(0.1)		(0.3)
Net carrying amount of impaired loans with specific reserve	2.5		4.7
Impaired loans with no specific reserve	0.0		0.0
Net carrying amount of impaired loans	2.5		4.7
Average recorded investment	4.2	[1]	7.2	[2]
Dealer | Retail
Financing Receivable, Impaired [Line Items]
Impaired loans with a specific reserve	0.0		0.0
Associated allowance	0.0		0.0
Net carrying amount of impaired loans with specific reserve	0.0		0.0
Impaired loans with no specific reserve	0.0		0.0
Net carrying amount of impaired loans	0.0		0.0
Average recorded investment	0.0	[1]	0.0	[2]
Customer Retail | Fleet
Financing Receivable, Impaired [Line Items]
Impaired loans with a specific reserve	23.3		21.7
Associated allowance	(3.2)		(3.5)
Net carrying amount of impaired loans with specific reserve	20.1		18.2
Impaired loans with no specific reserve	5.6		6.5
Net carrying amount of impaired loans	25.7		24.7
Average recorded investment	28.1	[1]	24.4	[2]
Customer Retail | Owner/Operator
Financing Receivable, Impaired [Line Items]
Impaired loans with a specific reserve	2.0		2.4
Associated allowance	(0.4)		(0.5)
Net carrying amount of impaired loans with specific reserve	1.6		1.9
Impaired loans with no specific reserve	0.3		0.3
Net carrying amount of impaired loans	1.9		2.2
Average recorded investment	$ 2.4	[1]	$ 2.5	[2]

[1] Represents the average during the 12 months ended June 30, 2016.

[2] Represents the average during the 12 months ended June 30, 2015.